ABSTRACT During forming operation of electrogalvanized steel sheets, the crystallographic orientation of the zinc coating may evolve from a pyramidal texture to a basal one. As a consequence, the adsorption of lubricant additives onto the zinc surface may be altered. Plane-strain compression tests and XRD analysis are carried out to study the texture evolution. After deformation, the samples are cleaned and their reactivity versus fatty acids are measured by ToF-SIMS analysis. It is shown that fatty acids adsorb much more strongly on a pyramidal oriented zinc surface than on a basal one

J-M Mataigne

M Repoux

V Vaché

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DownloProceedings of WTC2005 
World Tribology Congress III 
September 12-16, 2005, Washington, D.C., USA 
WTC2005-64372 
ADSORPTION OF A FATTY ACID ONTO A DEFORMED ELECTROGALVANIZED STEEL SHEET 
 
 
V. Vaché / CEMEF, Ecole des Mines de Paris, BP 207, Sophia Antipolis, 06904 France,  
email : veronique.vache@ensmp.fr 
 
 
M. Repoux / CEMEF, Ecole des Mines de Paris, BP 207, Sophia Antipolis, 06904 France,  
email : monique.repoux@ensmp.fr 
 
 
J-M. Mataigne / Arcelor Research SA, Voie Romaine, BP320, Maizieres les Metz, 57214 France,  
email : jean-michel.mataigne@arcelor.com 
 
Proceedings of WTC2005 
World Tribology Congress III 
September 12-16, 2005, Washington, D.C., USA 
WTC2005-64372 
ABSTRACT 
During forming operation of electrogalvanized steel sheets, 
the crystallographic orientation of the zinc coating may evolve 
from a pyramidal texture to a basal one. As a consequence, the 
adsorption of lubricant additives onto the zinc surface may be 
altered. Plane-strain compression tests and XRD analysis are 
carried out to study the texture evolution. After deformation, 
the samples are cleaned and their reactivity versus fatty acids 
are measured by ToF-SIMS analysis. It is shown that fatty acids 
adsorb much more strongly on a pyramidal oriented zinc 
surface than on a basal one. 
KEYWORDS 
Zinc-coating, crystallographic orientation, adsorption, 
plane-strain compression test, XRD, Tof-SIMS. 
 
 
INTRODUCTION 
Electrogalvanized coatings are very efficient for the 
protection of steel against corrosion and have good mechanical 
properties. For these reasons, they are widely used in 
automobile industry. 
The formability of zinc coated steel sheets has widely been 
studied for several years: In the boundary lubrication regime, it 
has been shown that the adsorption of additives is a key 
parameter for friction. During deformation, the zinc crystal 
orientation is affected but the influence of zinc crystal 
orientation on the adsorption of a fatty acid has not yet been 
studied. The purpose of the present work is to study the 
consequences of the zinc coated steels deformation on the zinc 
coating orientation and on the adsorption of a fatty acid. 
 
 
 
aded From: https://proceedings.asmedigitalcollection.asme.org on 06/28/2019 Terms of EXPERIMENTAL PROCEDURE 
Deformation tests were conducted using the plane strain 
compression test. The procedure is to compress the sample 
between two platens with a given load and speed. The 
deformation ε can be obtained by measuring the initial (ei) and 
final (ef) thicknesses: 
e
e
f
iln
3
2
=ε  
The orientation of zinc coatings was determined by X-ray 
diffraction (XRD). The relative orientation was estimated by 
comparing the orientation of the sample with a powder of zinc. 
The orientation of powder is random. The relative texture 
coefficient (RTC) was calculated via the measurement of 
diffracted intensities for the {hkil} plans. 9 Zn peaks were 
monitored. The percentage of each plan was used to 
characterize preferred orientation, similar to the procedure used 
by Shaffer [1]. The normalized intensity of each peak was then 
divided by the sum of the normalized intensities to yield an 
approximate fraction of each plane orientation (RTC). 
After indentation, the sample was cleaned in four solvents 
ultrasonic bath in order to entirely remove the lubricant used 
during the compression test. It was then immersed in a solution 
of oleic acid in hexadecane. Oleic acid (C18H34O2) has been 
chosen because it is one of fatty acid additives of usual 
lubricants. The concentration of oleic acid in hexadecane was 
adjusted at 1%. The sample was immersed vertically during 1 
minute. It was finally rinsed in hexane to remove excess of 
hexadecane, just before ToF-SIMS analysis (time-of-flight 
secondary ion mass spectrometry). 
The ToF-SIMS analysis was already used to quantify the 
adsorption of organosilanes on aluminum surfaces [2]. The 
interaction between fatty acid and zinc coating surface was also 1 Copyright © 2005 by ASME 
Use: http://www.asme.org/about-asme/terms-of-use
Downstudied by ToF-SIMS [3]. Thanks to the low primary ion dose 
impinging the surface (static mode), the uppermost layers are 
analyzed: surface reactions and molecular fragmentation could 
be studied. The experiments were performed on a Charles 
Evans TRIFT machine. Positive and negative secondary ion 
spectra were recorded at several locations of the sample: 
Thanks to the positive mass spectra, the quantity of zinc could 
be controlled. Negative mass spectra was used to study the 
adsorption of acid oleic because the de-protonated oleic acid 
molecular ion (C18H33O2)- is easily detected on them, whereas 
protonated ions (C18H35O2)+ exhibit very low intensities on 
positive mass spectra. Each analyzed area was 120 µm*120 
µm. The peak intensities given below are normalized over the 
total number of counts, to account for experimental variations 
from one sample to another.  
 
RESULTS 
The initial preferred orientation of “as-received” 
electrogalvanized coating is pyramidal with a low basal 
component. XRD analysis show that the texture evolved under 
the deformation. With a deformation larger or equal than 2, the 
predominant orientation was basal and no more pyramidal. 
Mean values obtained for 10 samples of each kind can be seen 
on Table 1. 
 
RTC (%) before deformation deformation ε = 2 
basal 3 65 
low angle 
pyramidal 
39 16 
high angle 
pyramidal 
39 11 
prismatic 19 8 
 
Table 1: Relative texture coefficient (RTC) values for the 
two samples: as received and after deformation – XRD analysis  
 
The role played by the orientation of zinc coating on the 
adsorption of fatty acid has been studied on these deformed 
samples. The Tof-SIMS technique is not a quantitative one, but 
it is possible to compare relative intensities for similar samples. 
 
 
 
Figure 1: Portions of negative Tof-SIMS mass spectra 
showing the most characteristics peaks of adsorption 
On negative mass spectra (Fig. 1a), the relative intensity of 
the de-protonated oleic acid peak (C18H33O2) shows the 
a
b
m/z
m/z 
loaded From: https://proceedings.asmedigitalcollection.asme.org on 06/28/2019 Terms ofreactivity of the fatty acid with the zinc coating. Moreover, on 
the negative mass spectra, the presence of zinc carboxylates 
compounds (Fig. 1b) can be seen and show the association 
between zinc and one, two or three fatty acid molecule: 
respectively ZnO(C18H33O2), 361 amu, ZnOH(C18H33O2)2, 643 
amu and Zn(C18H33O2)3, 908 amu. 
The normalized intensities of these peaks are given in 
Figure 2 for the electrogalvanized samples as-received 
(pyramidal orientation) and after deformation (basal 
orientation). All pyramidal peaks show higher intensities which 
can be traduced by a higher reactivity of fatty acid onto a 
pyramidal orientation zinc substrate than for a basal one.  
C18H33O2
0
1000
2000
3000
4000
5000
6000
7000
pyramidal basal
no
rm
al
iz
ed
 in
te
ns
ity
0
50
100
150
200
250
300
350
pyramidal basal
mono ol
bi ol
tri ol
 
Figure 2: Intensities of oleic acid, mono, bi and tri-zinc 
oleates normalized by the total number of counts, versus the 
sample orientation. Immersion for 1 minute, in 1% oleic acid – 
hexadecane bath (mean values for 10 experiments) 
 
CONCLUSION 
One of the consequences of the deformation with the plane 
strain compression test was the change of the zinc 
electrodeposited orientation from a pyramidal to a basal 
orientation. The effect of the orientation on the adsorption has 
been studied. Such work has shown that a pyramidal orientation 
is more favorable on the adsorption of a fatty acid than basal 
orientation. 
When large deformations of electrogalvanized steel sheet 
are necessary, it seems that good lubrication need other 
additives than fatty acids. 
ACKNOWLEDGMENTS 
This work is supported by ARCELOR. The authors 
gratefully acknowledge ARCELOR for providing the 
commercial material.  
REFERENCES 
 
[1] S.J. Shaffer, J.W. Morris, Jr., and H.R. Wenk, 1990, 
Zinc Based Steel Coating Systems: Metallurgy and 
Performance, ed. By G. Krauss and D.K. Matlock, TMS, 
Warrendale, PA, pp. 129-140.  
[2] L. Houssiau, P. Bertrand, 2001, Tof-SIMS study of 
organosilane self-assembly on aluminum surfaces, Applied 
Surface Science, Vol. 175-176, pp. 351-356. 
[3] E. De Castro, 2003, “Friction of galvanized strips in 
deep-drawing; a ToF-SIMS study of surface reactivity towards 
oleic acid and calcium sulfonates”, Ph.D. thesis, Ecole des 
Mines de Paris, France.  2 Copyright © 2005 by ASME 
 Use: http://www.asme.org/about-asme/terms-of-use


WTC2005-64372 ADSORPTION OF A FATTY ACID ONTO A DEFORMED ELECTROGALVANIZED STEEL SHEET

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WTC2005-64372 ADSORPTION OF A FATTY ACID ONTO A DEFORMED ELECTROGALVANIZED STEEL SHEET

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